Investigate keyword search inaccurate results

[kevindharmawan]

Run the quick_start_cli.md then ver_quick_start.py. The current version of keyword search or full text search (FTS) still missing some columns. The current investigation results are:

1. Results from the fts_query function in dindex_store/fulltext_index_duckdb.py with conjunctive := 1 is incomplete. For example, it wasn't able to find any column that contains "University of Chicago - Woodlawn".
2. I can confirm that the index builder runs correctly, at least for the case in number 1. I checked semi-manually by querying the raw data (in DuckDB) used by the FTS.
3. When conjunctive := 1 is removed, the results are not sorted from the best to worst.